| 摘要 |
<p>A floating sampler and directional bridge for use in characterizing the impedance of an integrated device under test from D.C. up to frequencies above 100 GHz. The directional bridge has the structure of a Wheatstone bridge with resistor values selected such that when the input impedance of the device under test matches the output impedance of the source, no voltage develops across two nodes of the bridge. When no impedance match exists, a floating diode/capacitor sampler comprised of two diode/capacitor pairs (D1, C1 ; D2, C2) driven by local oscillator (147) strobe pulses samples the voltage difference between the two nodes of the bridge and outputs an IF signal proportional to the difference. Another pair of diode/capacitor samples (D3, C3 ; D4, C4) outputs an IF signal proportional to the amplitude of the RF excitation waveform. <IMAGE></p> |
